I was trying to plan a big family reunion for the holidays last year and realized Southwest only opens their schedule in "chunks" rather than a rolling year. I kept checking every day in July, only to find out they were releasing the winter dates on a specific Thursday morning. I hopped on at 7:00 AM, and the price difference between that morning and the following evening was huge!
Checking their "Flight Schedules" page for the next release date is naturally the best way to plan ahead. If the dates aren't out yet, you can always book a placeholder trip and modify it later once the new schedule drops.
